When the wheel of an automobile rotates at high speed, it is important that the wheel is properly balanced. If it is not, that is, if its center of mass does not coincide with its center of rotation, the wheel will vibrate and bounce on the pavement causing a number of undesirable effects. Such vibrations impair the proper operation of the brakes, and the steering mechanism, and they cause excessive tire wear, increased maintenance costs and driver fatigue.
The common remedy in the case of passenger cars and other vehicles is to have the wheels balanced. This is ordinarily accomplished by attaching lead weights to the rims of the wheels. Most service stations have special equipment which they employ in the determination of the required size and location of the weights needed for the balancing of a given wheel. Each time a new or repaired tire is installed on a wheel, the balancing operation must be repeated. It is also desirable to rebalance a wheel periodically to correct any imbalance that might occur due to uneven tire wear.
Because such periodic maintenance is expensive and subject to neglect, there has been a continuing interest in the development of a balancing mechanism that can be permanently attached to a wheel. Such a balancing mechanism should preferably operate continuously as the wheel rotates, providing in some way a dynamic counterbalancing effect to offset any static imbalance existing in the wheel and tire assembly.